Microwave-assisted synthesis of blue-emitting cesium bismuth bromine perovskite nanocrystals without polar solvent

•Cs3Bi2Br9 perovskite nanocrystals in nonpolar solvents were synthesized by microwave-assisted approach.•Cs3Bi2Br9 nanocrystals exhibit a high PLQY of 35.8%.•A blue LED was fabricated by using the Cs3Bi2Br9 nanocrystals as color conversion materials. Lead halide perovskite nanocrystals (NCs) have attracted much attention due to their remarkable performances in optoelectronic applications, but their development is greatly limited by the lead toxicity and instability in environmental conditions. In this paper, we reported a simple microwave-assisted (MW-AT) method for the synthesis of non-toxic and stable all-inorganic Cs3Bi2Br9 perovskite NCs in nonpolar solvent. The as-prepared NCs show a highly efficient blue emission at 434 nm and 460 nm. The photoluminescence quantum yield (PLQY) of Cs3Bi2Br9 NCs is raised from 8.47% to 35.8% because of effective passivation of surface trap-states by BiOBr. In addition, a blue light-emitting diode (LED) are fabricated by coating Cs3Bi2Br9 NCs/silica composite onto a 365 nm GaN LED chip. This work provides a new synthetic path for preparing lead-free perovskite NCs, and demonstrates their promising application in solid-state lighting.